problem when scrolling on dimension 9150

alright...soo i just got this (new) used computer. It immediatly started crashing on me. A friend of mine came and tried to fix it. pretty much thinks it was the ram soo now i am down to 1 gb rather than 2 gb..

but the real problem happened when Windows was reinstalled. The only way i can think to describe it is to say that when i am scrolling through a page the page moves in a wave like motion, very choppy. The mouse moves smoothly it is only the picture. Also the picture (in an actual picture) is often split up, and the colours dont match at all. (very bad when my hobby is photography).

does anyone have any thoughts as to what the problem is. I was thinking maybe the drivers? but i honestly dont know what type of card i have this website says i have a card(CIRCUIT) GRAPICS 256. 7800 CTX UHMGA13  and my monitor is 21 inches.

thank you!!